In this article we describe preliminary experiments based on a technique originally devised by Holst and Clausing ͓G. Holst and P. Clausing, Physica ͑The Hague͒ 6, 48 ͑1926͔͒ whereby molecules are beamed onto a disk rotating at high speed and the point of desorption identified. This in principle provides a means for the direct determination of molecular residence times. Preliminary results indicate that the residence times of helium, nitrogen, oxygen, krypton, xenon and Suva ͑a refrigerant͒ on oxidized aluminum are not in the range of 0.1 ms-1 s. An experimental facet possibly indicating a residence time for carbon dioxide on oxidized aluminum at 27°C of 0.62 ms was identified. The possible application of the technique to gas separation is also discussed.